Methods and compositions for inhibiting apoptosis using serine protease inhibitors

ABSTRACT

The instant invention provides a method of treating an animal suffering a disease characterized by excessive apoptosis by administering a therapeutically effective amount of at least one serine protease inhibitor and thereafter monitoring a decrease in apoptosis. The inhibitor of the invention includes α 1 -antitrypsin or an α 1 -antitrypsin-like agent, including, but not limited to oxidation-resistant variants of α 1 -antitrypsin, and peptoids with antitrypsin activity. The diseases treatable by the invention include cancer, autoimmune disease, sepsis neurodegenerative disease, myocardial infarction, stroke, ischemia-reperfusion injury, toxin induced liver injury and AIDS. The method of the invention is also suitable for the prevention or amelioration of diseases characterized by excessive apoptosis.

The present application claims the priority of U.S. provisional application Ser. No. 60/123,167, filed Mar. 5, 1999, the entire disclosure of which is incorporated by reference herein.

1. FIELD OF THE INVENTION

The present invention relates to compositions and methods useful in the inhibition of apoptosis. Likewise, the present invention relates to methods of treating diseases associated with excessive or unregulated apoptosis.

2. BACKGROUND OF THE INVENTION

Normal development, growth, and function of multi-cellular organisms require control both of processes that produce cells and of those that destroy cells. Mitosis, or cell proliferation, is highly regulated except in specific states termed cell proliferative diseases. There also exist processes for destruction of cells. Cells in multi-cellular organisms die by two distinct mechanisms. One method, termed necrotic cell death, is characterized by cytoplasmic swelling, rupturing of cellular membranes, inflammation and disintegration of subcellular and nuclear components. The other method, apoptosis, by contrast, is characterized by more organized changes in morphology and molecular structure. Apoptotic cells often condense and shrink, in part, by cytoplasmic membrane blebbing, a process of shedding small packets of membrane-bound cytoplasm. The chromosomes of such cells condense around the nuclear periphery. Generally, in apoptotic cells the chromosomes are degraded by specific nucleases that cleave DNA to produce regular-sized fragments. Importantly, there is a requirement for new mRNA and protein expression during the early stages of some forms of apoptosis, indicating that it is an active process. Macrophages envelop and phagocytose apoptotic cells, thereby digesting and recycling the cellular components.

Changes in cell morphology during apoptosis are profound. Detection of the many morphological changes associated with apoptosis is detected using light microscopy or electron microscopy. In particular, electron microscopy is useful for evaluating cells with a high nucleus to cytoplasm ratio and light microscopy is useful for immuno- and histochemistry. The changes characteristic of apoptosis include decreased volume, compaction of cytoplasmic organelles, and increased cell density. In addition, microvilli disappear, blebs of cytoplasm form at the cell surface, and the blebs dissociate from the cell to form apoptotic bodies. Other techniques are useful in the analysis of apoptosis including confocal, laser, and scanning microscopy, fluorescent DNA dye binding, and molecular techniques. The molecular techniques permit detection of apoptosis in formalin-fixed and embedded tissue, including terminal deoxynucleotidyl transferase (TdT)-mediated dUTP-biotin nick end labeling (TUNEL) and in situ, end labeling (ISEL).

Protease Involvement

The progression of apoptosis requires the coordinated action of specific proteases. The proteases can be inhibited by inhibitors including N-tosyl-L-phenylalanylchloromethyl ketone (TPCK) and N-tosyl-L-lysylchloromethyl ketone (TLCK). Furthermore, at least 10 cysteine proteases related to interleukin-1-βconverting enzyme have been identified as components of apoptotic signaling pathways. The interleukin-1-β converting enzyme-like proteases are referred to as caspases and are identified and have been isolated by molecular cloning.

In addition, there are other proteases involved in apoptosis including the granzymes and cathepsin. Granzyme B is a serine esterase that can activate several members of the caspase family. Granzyme B may be a mediator of cytotoxic T lymphocyte induced apoptosis. Granzyme B is known to cleave and initiate caspase 3, a likely component of its mode of action. Granzyme B may also initiate nuclear events associated with cytotoxic T lymphocyte-induced apoptosis, consistent with observations that it is passively transported into the nucleus and bind to nuclear proteins. One action of Granzyme B may be in the regulation of conversion of proCPP32 to CPP32. CPP32 is itself a protease thought to cleave poly(ADP-ribose) polymerase (PARP) and may also activate prolamin protease resulting in activation of lamin protease. Cleavage of lamins and inactivation of the DNA repair enzyme PARP promote the development of apoptotic changes in the cell nucleus.

Serine Proteases

In contrast to cysteine proteases, the role of serine proteases in apoptosis is controversial. For a general discussion, see Kaufmann, S. Cancer Res 1993, 53, 3976. For example, it is known that the serine protease inhibitor TLCK inhibits apoptosis-associated proteolysis. However, TLCK is known to inhibit cysteine proteases in addition to serine proteases, and has recently been shown to inhibit a member of the interleukin-1β converting enzyme family. Thus, the effect of TLCK on apoptosis is likely not mediated by an effect as a serine protease inhibitor, given the more established role of cysteine proteases in apoptosis.

Cellular Protease Targets

Multiple polypeptide species must be modified to produce the wide range of morphological manifestations that characterize apoptosis. For example, the lamins are nuclear intermediate filament proteins that form a fibrous layer between the inner nuclear membrane and the chromatin. The resulting lamina is thought to play a role in maintaining nuclear shape and in mediating chromatin-nuclear membrane interactions. Thus, the apoptosis-associated changes in nuclear shape might require lamin reorganization. Another polypeptide that is cleaved during apoptosis is poly (ADP-ribose) polymerase (PARP). PARP is an abundant nuclear enzyme that catalyzes the conversion of the dinucleotide NAD⁺ to nicotinamide and protein-linked chains of ADP-ribose. Yet, the detailed role of PARP in the process of apoptosis is unclear. Studies have suggested that inhibitors of PARP delay apoptosis and yet other studies have suggested that inhibition of PARP increases the fragmentation of DNA during apoptosis. It is clear, however, that PARP is proteolytically degraded late in apoptosis.

Another proteolytic enzyme target during apoptosis is the U1 ribonuclear protein (U1-70k), a molecule required for splicing of precursor mRNA that is itself cleaved to an inactive 40 kDa fragment during apoptosis. The cleavage of this polypeptide would result in cessation of RNA processing.

Other substrates for protease activity during apoptosis include fodrin, the PITSLREβ1 protein kinase, the adenomatous polyposis coli (APC) protein, the retinoblastoma gene product, terminin, and nuclear matrix proteins. Cleavage of fodrin, an abundant membrane associated cytoskeletal protein, has been detected during apoptosis in a variety of cell lines. PITSLREβ1 protein kinase, a member of the P34^(cdc2) gene family has been shown to induce mitotic delay in CHO cells. Members of this family appear to be cleaved during apoptosis. For example, recent studies indicate that PITSLREβ1 kinase is proteolytically cleaved during FAS- or steroid-induced apoptosis in T-cells. Another major group of protease targets is the caspases, themselves proteases, or precursor forms of caspases. Yet another group of proteins which may well be downstream effectors of caspase-mediated apoptosis, include the protein kinases PKCδ, PKCθ, MEKK1, the sterol regulatory element binding proteins 1 and 2, and the DNA fragmentation factor (DFF).

Diseases Associated with Apoptosis

Increased levels or apparent induction of apoptosis is associated with a number of diseases including cancer, autoimmune diseases including rheumatoid arthritis, neurodegenerative diseases, myocardial infarction, stroke, sepsis, ischemia-reperfusion injury, toxin induced liver injury, and AIDS (see Kidd, V. J., Annu Rev Physiol, 1998, 60, 533; List, P. J. M., et al., Arterioscler Thromb Vasc Biol 1999, 19, 14; Jabs, T., Biochem Pharmacol 1999 57, 231; Deigner, H. P., et al. Curr Med Chem 1999, 6, 399). The apoptosis appears to be mediated by oxygen free radicals [O] which have been implicated in various disorders including atherosclerosis, diabetes, sepsis, Alzheimer's disease, arthritis, muscular dystrophy, cancer, Downs syndrome, multiple sclerosis, HIV infection and other inflammatory diseases (Morel, J. B. and Dangle, J. L., Cell Death Differ 1997, 4, 671; Beal, M. F., Curr Opin Neurobiol 1996, 6, 661).

3. SUMMARY OF THE INVENTION

The present invention is directed to a method of treating an animal or a patient suffering from a disease characterized by excessive apoptosis. The method of the invention comprises administering a therapeutically effective amount of at least one serine protease inhibitor and subsequently monitoring a decrease in apoptosis.

In a preferred embodiment, the animal is a human. In another preferred embodiment, the agent is α₁-antitrypsin (ATT) or an α₁-antitrypsin-like agent. In addition, peptides of interest are homologous and analogous peptides. All homologues are natural peptides which have sequence homology, analogs will be peptidyl derivatives, e.g., aldehyde or ketone derivatives of such peptides. Furthermore, agents with α₁-antitrypsin-like activity are also envisioned. In this regard, peptide derivatives of α₁-antitrypsin, compounds like oxydiazole, thiadiazole, CE-2072, UT-77, and triazole peptoids are preferred. The α₁-antitrypsin-like agent includes, but is not limited to, small organic molecules including naturally occurring, synthetic, and biosynthetic molecules, small inorganic molecules including naturally-occurring and synthetic molecules, natural products including those produced by plants and fungi, peptides, variants of α₁-antitrypsin, chemically modified peptides, and proteins. It is a further embodiment of this invention that an individual with risk for a pathological disease or condition that is precipitated at least in part by excessive apoptosis, can be treated to prevent the onset of acute disease with a prophylactic treatment of an agent exhibiting α₁-antitrypsin or α₁-antitrypsin-like activity.

A further embodiment of the invention envisions a method for inhibiting apoptosis in an in vitro mammalian cell culture, an ex vivo mammalian tissue culture, or a mammalian organ, comprising providing to a cell culture, tissue culture, or organ, an amount of a serine protease inhibitor sufficient to inhibit apoptosis in the cell culture, tissue culture, or organ. In the aforementioned embodiment, a measured amount of apoptosis is indicative of expression or activity of apoptosis.

A still further embodiment of the invention directed to a method of inhibiting apoptosis comprises allowing a serine protease inhibitor to bind to a protease and measuring the decrease in apoptosis. Another embodiment of the invention is directed to a method of inhibiting apoptosis comprising allowing a serine protease inhibitor to bind to a cell surface receptor and measuring the decrease in apoptosis.

A yet still further embodiment of the invention is directed to use of oxidation-resistant and free-radical resistant inhibitors of serine proteases. In this regard, the oxidation-sensitive Met³⁵⁸ in α₁-antitrypsin can, by genetic engineering, be replaced by Val³⁵⁸-α₁-antitrypsin, which results in a molecule termed Val³⁵⁸-α₁-antitrypsin. Val³⁵⁸-α₁-antitrypsin is a more potent inhibitor of neutrophil elastase than is Met³⁵⁸-α₁-antitrypsin possibly because of the stability of Val³⁵⁸-α₁-antitrypsin to the neutrophil oxidative burst. The Met at position 358 is replaced with any hydrophobic or neutral oxidation-resistant amino acid residue, including: alanine, asparagine, α-amino butyric acid, anthranilic acid, β-cyanoalanine, β-(3,4-dihyroxyphenyl) alanine, 3,5-diiodotyrosine, glutamine, glycine, homoserine, 3-hydroxyanthranilic acid, 5-hydroxy-indole-3-acetic acid, 3-hydroxykynurenine, hydroxyproline, 5-hydroxy-tryptophan, indoleacetic acid, 3-iodotyrosine, isoleucine, allo-isoleucine, leucine, leucylglycine, norleucine, norvaline, phenylalanine, proline, prolylglycine, serine, threonine, allo-threonine, throxine, 3,5,3′-tri-iodo-thyronine, tryptophan, and tyrosine. The amino acid substitutions are effected by genetic engineering, chemical modification, or a combination thereof.

4. BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 illustrates the effect of al-antitrypsin and the peptoid CE-2072 on apoptosis in RCG Neuron (rat cerebral granule) cells, also termed RCGC.

5. DETAILED DESCRIPTION OF THE INVENTION

5.1 Standard Methods

In accordance with the present invention there can be employed conventional molecular biology, microbiology, and recombinant DNA techniques within the skill of the art. Such techniques are explained fully in the literature. See, e.g., Sambrook, Fritsch & Maniatis, Molecular Cloning: A Laboratory Manual, Second Edition 1989, Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.; Animal Cell Culture, R. I. Freshney, ed., 1986).

5.2 Serine Protease Inhibitors

The current invention teaches methodologies and agents for treating animals and patients that suffer from a disease involving excessive apoptosis. The methods involve administration of therapeutically effective amounts of at least one serine protease inhibitor and testing for changes in apoptosis by any of several means known in the art. The serine proteases that are inhibited by the agent of the invention include trypsin, elastase, cathepsin G, tryptase TL-2, Factor Xa and proteinase-3. The methods further involve inhibition of oxygen free radicals and inhibition of oxygen free radical formation by serine protease inhibitors. The method further includes a pharmaceutically acceptable carrier, any of which are known in the art. Serine protease inhibitors include α₁-antitrypsin, or α₁-antitrypsin-like agents. In the latter group are included the oxydiazole, thiazole, triazole peptoids, or some combination of these agents. The serine protease inhibitor is optionally derivatized chemically by esterification, acetylation or amidation.

There are numerous diseases that are characterized by excessive apoptosis. Among these diseases are cancer, autoimmune diseases, neurodegenerative diseases, myocardial infarction, stroke, ischemia-reperfusion injury, toxin-induced liver injury, sepsis and AIDS.

A preferred embodiment of the invention is directed toward the treatment of myocardial infarction. Another preferred embodiment of the invention is directed toward treatment of stroke, also known as brain ischemia or cerebrovascular accident. The therapeutically effective amounts of the serine protease inhibitors are sufficient to bring the concentration of the added agent in the biological fluid of the individual to between about 10 pM and 2 mM. For α₁-antitrypsin the effective concentrations correspond to between about 5 nanograms per milliliter to about 10 milligrams per milliliter of the biological fluid of the individual. The biological fluid of the individual is calculated from the total body weight of the individual or, in diseases that are localized to specific body compartments, from the volume of the compartment. Biological fluid can include, but is not limited to, blood, plasma, serum, lymph, tears, saliva, cerebrospinal fluid, or combinations thereof.

In a preferred embodiment of the invention, the therapeutically effective amount is sufficient to bring the concentration in the biological fluid to between 0.5 μM and 200 μM, preferably between 5 μM and 200 μM, most preferably about 100 μM. The agent is advantageously administered according to the weight of the subject. Administration of the therapeutically effective amount of serine protease inhibitor can be in a bolus, for example, of about 0.001 to 7 g of α₁-antitrypsin-like agent or about 1 to 70 g of α₁-antitrypsin, per kg of body weight of the subject. Preferred amounts are about 0.01 g/kg body weight of oxydiazole, thiazole, or triazole peptoids, and about 1 g/kg body weight of natural or variant α₁-antitrypsin.

The administration of the agent in the invention can be performed parenterally, orally, vaginally, nasally, buccally, intravenously, intramuscularly, subcutaneously, rectally, intrathecally, epidurally, transdermally, intracerebroventricularly, or combinations thereof.

In another embodiment of the invention, the agent is administered continuously or intermittently by osmotic pump or by implanted osmotic pump, including those of the Alza Corporation. It is a further embodiment of the invention that the therapeutically effective amount of the serine protease inhibitor is administered between about once daily to about once hourly. In a more preferred embodiment of the invention, the serine protease inhibitor is administered twice per day. It is a further embodiment of the invention that the monitoring of changes in apoptosis be performed on tissue obtained from an animal or patient. Any of several methods for monitoring apoptosis, well known in the art, are suitable.

A further method of the invention is directed to encouraging the binding of a serine protease inhibitor to a protease and observing a change in apoptosis. In this embodiment, the serine protease inhibitor is α₁-antitrypsin or α₁-antitrypsin-like agent. The α₁-antitrypsin-like agent is also a substituted oxydiazole, substituted thiadiazole, substituted triazole peptoids, or any combination of these agents.

Apoptosis is associated with free radical production, including oxygen free radicals. Free radicals are known to inactivate natural α₁-antitrypsin. Therefore, it is desirable to supplement α₁-antitrypsin in blood with sufficient α₁-antitrypsin-like activity which is not inactivated by free radicals. Alternatively, a mutant α₁-antitrypsin resistant to inactivation by free radicals, or administration of a synthetic molecule that is not inactivated by free radicals, is contemplated. Also, co-administration of a free radical scavenger or inhibitor is contemplated.

The present invention is not limited by the mechanism of action of α₁-antitrypsin inhibitors in decreasing apoptosis. Thus the apoptosis may be mediated by tumor necrosis factor, by anti-Fas or by any other mechanism. In a particular embodiment of the invention apoptosis not mediated by tumor necrosis factor is inhibited by the α₁-antitrypsin-like agents of the invention. Moreover, the agents of the invention are effective to inhibit apoptosis in a plurality of organs including, but not limited to brain, heart, spinal cord, peripheral nerves, skin, stomach, liver, pancreas, gut, ovaries, testis, and endocrine glands.

It is to be understood hat the present invention is not limited to the examples described herein, and other serine protease inhibitors known in the art are used within the limitations of the invention. For example, one skilled in the art can easily adopt inhibitors as described in WO 98/24806, which discloses substituted oxadiazole, thiadiazole, and triazole as serine protease inhibitors. U.S. Pat. No. 5,874,585 discloses substituted heterocyclic compounds useful as inhibitors of serine proteases, including: (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(2-phenylethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(2-methoxybenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(trifluoromethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1,3-(3-(5-(methyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl[-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(difluoromethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(benzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-methoxybenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(2,6-difluorobenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(s)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(trans-styryl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonly)-L-valyl-N-[1-(3-(5-(trans-4-trifluoromethylstyryl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(trans-4-methoxystyryl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-thienylmethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(phenyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; and (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-phenylpropyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide. U.S. Pat. No. 5,216,022 teaches other small molecules useful for the practice of this invention, including: (benzyloxycarbonyl)-L-valyl-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide (also known as CE-2072); (benzyloxycarbonyl)-L-valyl-N-[1-(2-(3-(methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(2-(5-(methyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(2-(5-(3-trifluoromethylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(2-(5-(4-dimethylamino benzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(2-(5-(1-napthylenyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-[1-(3-(5-(3,4-methylenedioxybenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[-1-(3-(5-(3,5-dimethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3,5-dimethoxybenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3,5-ditrifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-methylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(biphenylmethine)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(4-phenylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-phenylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-phenoxybenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl[-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(cyclohexylmethylene)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-trifluoromethyldimethylmethylene)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(1-napthylmethylene)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3-pyridylmethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(3,5-diphenylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; (benzyloxycarbonyl)-L-valyl-N-[1-(3-(5-(4-dimethylaminobenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]-L-prolinamide; 2-(5-[(benzyloxycarbonyl)amino]-6-oxo-2-(4-fluorophenyl)-1,6-dihydro-1-pyrimidinyl]-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-(S)-2-methylpropyl]acetamide; 2-(5-amino-6-oxo-2-(4-fluorophenyl)-1,6-dihydro-1-pyrimidinyl]-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 2-[5-[(benzyloxycarbonyl)amino]-6-oxo-2-(4-fluorophenyl)-1,6-dihydro-1-pyrimidinyl]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-(S)-2-methylpropyl]acetamide; 2-[5-amino-6-oxo-2-(4-fluorophenyl)-1,6-dihydro-1-pyrimidinyl]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-methylpropyl]acetamide; (pyrrole-2-carbonyl)-N-(benzyl)glycyl-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]amide; (pyrrole-2-carbonyl)-N-(benzyl)glycyl-N-[1-(3-(5-(3-trifluoromethylbenzyl)(1,2,4-oxadiazolyl)-(S)-methylpropyl]amide; (2S,5S)-5-amino-1,2,4,5,6,7-hexahydroazepino-[3,2,1]-indole-4-one-carbonyl-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-(R,S)-2-methylpropyl]amide; BTD-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]amide; (R,S)-3-amino-2-oxo-5-phenyl-1,4-benzodiazepine-N-[1-(2-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; (benzyloxycarbonyl)-L-valyl-2-L-(2,3-dihydro-1H-indole)-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]amide; (benzyloxycarbonyl)-L-valyl-2-L-(2,3-dihydro-1H-indole)-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]amide; acetyl-2-L-(2,3-dihydro-1H-indole)-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]amide; 3-(S)-(benzyloxycarbonyl)amino)-ε-lactam-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 3-(S)-(amino)-ε-lactam-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide trifluoroacetic acid salt; 3-(S)-[(4-morpholinocarbonyl-butanoyl)amino]-ε-lactam-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(R,S)-methylpropyl]acetamide; 6-[4-fluorophenyl]-ε-lactam-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 2-(2-(R,S)-phenyl-4-oxothiazolidin-3-yl]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 2-(2-R,S)-phenyl-4-oxothiazolidin-3-yl]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl(hydroxymethyl)-2-(S)-methylpropyl]acetamide; 2-(2-(R,S)-benzyl-4-oxothiazolidin-3-yl]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 2-(2-(R,S)-benzyl-4-oxothiazolidin-3-yl oxide]-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(R,S,)-methylpropyl]acetamide; (1-benzoyl-3,8-quinazolinedione)-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; (1-benzoyl-3,6-piperazinedione)-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; (1-phenyl-3,6-piperazinedione)-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; (1-phenyl-3,6-piperazinedione)-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)]-2-(S)-methylpropyl]acetamide; 3-[(benzyloxycarbonyl)amino]-quinolin-2-one-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 3-[(benzyloxycarbonyl)amino]-7-piperidinyl-quinolin-2-one-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 3-(carbomethoxy-quinolin-2-one-N-[1-(2-(5-(3-methybenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 3-(amino-quinolin-2-one)-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 3-[(4-morpholino)aceto]amino-quinolin-2-one-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 3,4-dihydro-quinolin-2-one-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 1-acetyl-3-(4-fluorobenzylidene)piperazine-2,5-dione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 1-acetyl-3-(4-dimethylaminobenzylidene)piperazine-2,5-dione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 1-acetyl-3-(4-carbomethoxybenzylidene)piperazine-2,5-dione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 1-acetyl-3-[(4-pyridyl)methylene]piperazine-2,5-dione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-benzyl-3-(R)-benzyl-piperazine-2,5-dione]-N-[1-(2-[5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-benzyl-3-(S)-benzylpiperazine-2,5-dione]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-benzyl-3(R)-benzylpiperazine-2,5-dione]-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-benzyl-3-(S)-benzylpiperazine-2,5-dione]-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-benzyl-3-(S)-benzylpiperazine-2,5-dione]-N-[1-(3-(5-(2-dimethylaminoethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-methyl-3-(R,S)-phenylpiperazine-2,5-dione]-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[methyl-3-(R,S)-phenylpiperazine-2,5-dione]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 4-[1-(4-morpholinoethyl)-3-(R)-benzylpiperazine-2,5-dione]-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 5-(R,S)-phenyl-2,4-imidazolidinedione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 5-(R)-benzyl-2,4-imidazolidinedione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 5-(S)-benzyl-2,4-imidazolidinedione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 5-(S)-benzyl-2,4-imidazolidinedione-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 5-(R)-benzyl-2,4-imidazolidinedione-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; 1-benzyl-4-(R)-benzyl-2,5-imidazolidinedione-N-[1-(2-(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; and 1-benzyl-4-(R)-benzyl-2,5-imidazolidinedione-N-[1-(3-(5-(3-trifluoromethylbenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-methylpropyl]acetamide; among others.

Yet another embodiment of the invention is directed toward the inhibition of apoptosis resulting from the interaction between a serine protease inhibitor and a cell surface receptor and resulting in a measurable decrease in apoptosis. The serine protease inhibitor of this embodiment is an α₁-antitrypsin or an α₁-antitrypsin-like agent. The α₁-antitrypsin-like agents includes substituted oxydiazoles, substituted thiadiazole, substituted triazole peptoids, or combinations of these agents. The substituted oxydiazole, thiadiazole, and triazole peptoids are synthesized de novo or derivatized from existing compounds.

5.3 Diseases Addressed by the Invention

Specific diseases or disorders for which the therapeutic methods of the invention are beneficial include wasting diseases of various types. The diseases include cancer, neurodegenerative diseases, myocardial infarction, and stroke. The cancers include bladder, breast, kidney, leukemia, lung, myoloma, liposarcoma, lymphoma, tongue, prostate, and uterine cancers. The method of the invention is also applied to Alzheimer's disease, muscular dystrophy, Downs Syndrome, sepsis, HIV infection, multiple sclerosis, arteriosclerosis, diabetes, and arthritis. In fact, the invention is applied to any disease associated with elevated levels of apoptosis.

5.4 Modes of Administration

Modes of administration of the various therapeutic agents used in the invention are exemplified in the examples below. However, the agents are delivered by any of a variety of routes including: by injection (e.g., subcutaneous, intramuscular, intravenous, intra-arterial, and intraperitoneal), by continuous intravenous infusion, transdermally, orally (e.g., tablet, pill, liquid medicine), by implanted osmotic pumps (e.g., ALZA Corp.), by suppository or aerosol spray.

Those skilled in the art of biochemical synthesis will recognize that for commercial scale quantities of peptides, such peptides are preferably prepared using recombinant DNA techniques, synthetic techniques, or chemical derivatization of biologically or chemically synthesized peptides.

The compounds of the present invention are used as therapeutic agents in the treatment of a physiological, or especially, pathological, condition caused in whole or part by uncontrolled serine protease and apoptosis activity. The peptides or peptoids can be administered as free peptides, free peptoids, or pharmaceutically acceptable salts thereof. The terms used herein conform to those in Budavari, S. (Ed.), “The Merck Index, An Encyclopedia of Chemicals, Drugs, and Biologicals,” Merck Company, Inc., twelfth edition. The term “pharmaceutically acceptable salt” refers to those acid addition salts or methyl complexes of the peptides which do not significantly or adversely affect the therapeutic properties including efficacy and toxicity, of the peptides and peptoids. The peptides and peptoids are administered to individuals as a pharmaceutical composition which, in most cases, will comprise the peptide, peptoid, and/or pharmaceutical salts thereof with a pharmaceutically acceptable carrier. The term “pharmaceutically acceptable carrier” refers to those solid and liquid carriers, which do not significantly or adversely affect the therapeutic properties of the peptides.

The pharmaceutical compositions containing peptides and/or peptoids of the present invention are administered to individuals, particularly humans, either intravenously, subcutaneously, intramuscularly, intranasally, orally, topically, transdermally, parenterally, gastrointestinally, transbronchially, and transalveolarly. Topical administration is accomplished by a topically applied cream, gel, rinse, etc. containing therapeutically effective amounts of inhibitors of serine proteases. Transdermal administration is accomplished by administration of a cream, rinse, gel, etc. capable of allowing the inhibitors of serine proteases to penetrate the skin and enter the blood stream. Parenteral routes of administration include, but are not limited to, direct injection such as intravenous, intramuscular, intraperitoneal, or subcutaneous injection. Gastrointestinal routes of administration include, but are not limited to, ingestion and rectal. Transbroncheal and transalveolar routes of administration include, but are not limited to, inhalation, either via the mouth or intranasally, and direct injection into an area, such as through a tracheotomy, endotracheal tube, or aspirated through a respiratory mist. In addition, osmotic pumps are used for administration. The necessary dosage will vary with the particular condition being treated, method of administration, and rate of clearance of the molecule from the body.

6. EXAMPLES

The following specific examples are provided to better assist the reader in the various aspects of practicing the present invention. As these specific examples are merely illustrative, nothing in the following descriptions should be construed as limiting the invention in any way. Such limitations are, of course, defined solely by the accompanying claims.

6.1 Effect of Therapy with α₁-Antitrypsin Following Experimental Myocardial Infarction or Stroke

Rats (female, 250-300 g each) are randomly assigned to one of four groups: myocardial infarction control, stroke control, myocardial infarction, and stroke. The rats are subjected to a 30 minute ligation of the coronary arterial supply (for the myocardial infarction group) or the left carotid artery (for the stroke group), followed by release of the ligature. Sham operated controls receive the cut-down and manipulation of the artery but without ligation. Immediately preceding the ligation or sham ligation, half of the animals in each group (by random selection) receive α₁-antitrypsin (sufficient to achieve a 50 μM concentration of added agent in the blood, or in the alternative, an amount equal to 10 mg/kg body weight) and the other half receive a body-weight equivalent volume of AAT vehicle, intravenously. The AAT vehicle is phosphate-buffered saline, or optionally, any pharmaceutically acceptable carrier. At twenty-four hours after release of the sham or actual ligation the animals are sacrificed and the hearts and brains removed for analysis of the amount of apoptosis. In other experiments the dosage of α₁-antitrypsin administered is varied between the amounts necessary to produce a concentration of 10 μM and 250 μM in the blood. In general, a concentration of 5 mg/ml of α₁-antitrypsin is equivalent to about 100 μM. In yet other experiments the frequency of administration is varied from once per day to four times per day. Likewise, antielastase and antiproteinase are used.

6.2 Anti-Apoptosis Therapy for Septic Shock

Protection of mouse L929 cells from apoptotic effects of TNF are evaluated using: the agents α₁-antitrypsin; (Benzyloxycarbonyl)-L-Valyl-N-[1-2-3(5-(3-methylbenzyl)-1,3,4-oxadiazolyl)carbonyl)-2-(S)-Methylpropyl]-L-Prolinamide; (Benzyloxcarbonyl)-L-Valyl-N-[1-(3-(5-(2-Phenylethyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-Methylpropyl]-L-Prolinamide; and (Benzyloxcarbonyl)-L-Valyl-N-[1-(3-(5-(2-Methoxybenzyl)-1,2,4-oxadiazolyl)carbonyl)-2-(S)-Methylpropyl]-L-Prolinamide L929. Cells (10⁵ cells/well) are treated with 300 ng/ml of human Tumor Necrosis Factor (TNF) with or without the agent (added one hour prior to TNF addition) at 0.02, 0.1, 0.2, 1.0, 2.0 and 10 mg agent/ml. One day later the cells are stained for viability using 2′-[4-hydroxyphenyl]-5-[4-methyl-1-piperazinyl]-2,5′-bi-1H-benzimidazole and fluorescence analyzed for apoptosis using a Leitz fluorescence microscope. The results are evaluated in terms of the dose response to the agent.

6.3 Free Radical Scavengers as Co-Inhibitors of Apoptosis

Agents that reduce free radical levels do not directly prevent the oxidizing effect of free radicals. Therefore, it is advantageous to administer two or three independently acting agents, as opposed to a single agent. Thus, one preferred embodiment of the process is the co-administration of α₁-antitrypsin and a free radical scavenger, such as glutathione (1 mg/kg body weight).

6.4 Free Radical Scavengers as Co-Inhibitors of Apoptosis

In yet another embodiment of the invention, oxidation-resistant α₁-antitrypsin variants are used to avoid inactivation by excess free radicals. As an example, synthetic α₁-antitrypsin or recombinant α₁-antitrypsin produced with alternative and oxidation-resistant amino acid sequences are embodiments of the invention.

6.5 Effect of AAT and CE-2072 on Apoptosis in RCG Neuron Cells

RCG neuronal cells are seeded into cell culture dishes in 400 μl cell culture medium (Eagle's basal medium, BME) containing 10% (v/v) FBS. At day two the now conditioned medium is removed and the cells are treated for 10 hours as follows:

Group Condition Treatment 1. negative control conditioned medium with serum 2. positive control BME without serum 3. experimental BME without serum, with IGF-I (50 ng/mL) 4. experimental BME without serum, with lyophilized AAT (50 μM) 5. experimental BME without serum, with soluble AAT (50 μM) 6. experimental BME without serum, with CE-2072 (60 μM) in DMSO 7. diluent control BME without serum, with vehicle 8. DMSO control BME without serum, with DMSO

Then the medium is replaced with 4% (w/v) paraformaldehyde, incubated for 15 minutes at room temperature, and the cells stained with Hoechst dye 33258 (8 μg/m1) for 15 minutes at room temperature. The apoptosis in the cells is evaluated using a fluorescence microscope by an evaluator blinded to the method of treatment. The results are shown in FIG. 1.

The apoptosis induced by depletion of serum is blocked by lyophilized α₁-antitrypsin and by agent CE-2072 (a synthetic inhibitor of serine protease). The latter is formally known as benzyloxcarbonyl-L-valyl-N-[1-(2-[5-(3-methylbenzyl)-1,3,4-oxadiazolyl] carbonyl)-2-(S)-Methylpropyl]-L-prolinamide.

6.6 Amelioration of Ischemia in Donor Organs During Transport and Transplant

Human donor organs, including kidneys, are subject to ischemia during transport, which can last up to several hours. Biopsies (3 mm) are removed from the top medial surface of donor kidneys undergoing transport prior to implantation, and grouped by time after removal from the donor: 1-2 hours, 2-4 hours, and greater than 4 hours. Donor kidneys transplanted within one hour serve as the first control and the contralateral kidney serves as the second control. Half of the donor kidneys are treated with α₁-antitrypsin (10 mg/ml fluid) upon removal from the donor to inhibit apoptosis.

6.7 Therapy with Oxidation-Resistant Recombinant α₁-Antitrypsin Variants

Val³⁵⁸-antitrypsin and Ile³⁵⁸-antitrypsin are produced from the appropriate nucleotide sequences by methods well known in the art, including construction of a plasmid, transfection of the host E. coli, selection of transfected colonies, expansion of the culture, and isolation and purification of the mutant gene product. Amounts of the recombinant agents effective in inhibiting apoptosis, excessive clotting, neutrophil extravasation, ischemia-reperfusion injury, or myocardial damage are applied in an experimental model of myocardial infarction (see Example 6.1, supra). Effective amounts are between 0.03 and 7 g/kg body weight, for example, about 0.5 g/kg. In some experiments the amount of variant antitrypsin is measured in the blood or other biological fluid. In those tests sufficient variant antitrypsin is administered to provide a concentration of about 1 μM to about 100 μM in the blood or biological fluid.

6.8 Effect of α₁-Antitrypsin on Apoptosis

Primary rat brain granule cells are pretreated for one hour in the absence or presence of α₁-antitrypsin (3.0 mg/ml), followed by replacement of the cell culture medium with either control medium containing 10% (vol/vol) fetal bovine serum, medium devoid of fetal bovine serum, or medium devoid of fetal bovine serum but containing α₁-antitrypsin. After 24 hours of culture the level of apoptosis is measured. α₁-Antitrypsin completely reverses the apoptosis associated with serum depletion, which results in cell death.

Throughout this application various publications and patents are referenced. The disclosures of these publications and patents in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which this invention pertains. While the invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure has come within known or customary practice within the art to which the invention pertains and as can be applied to the essential features here before set forth and as follows in the scope of the appended claims. 

1. A method of treating muscular dystrophy, multiple sclerosis, arteriosclerosis, neurodegenerative disease, myocardial infarction, or stroke in a subject in need of such a treatment, said method comprising: inhibiting apoptosis in the subject by administering a therapeutically effective amount of α₁-antitrypsin, an oxidation-resistant α₁-antitrypsin Met358 variant or a free radical-resistant α₁-antitrypsin M358 variant.
 2. The method of claim 1, wherein the neurodegenerative disease is Alzheimer's disease or Downs Syndrome.
 3. The method of claim 1, in which the subject is a human.
 4. The method of claim 1, wherein the effective amount of α₁-antitrypsin, an oxidation-resistant α₁-antitrypsin Met358 variant, or a free radical-resistant α₁-antitrypsin M358 variant is at least 0.001 g/kg body weight and no greater than 1 g/kg body weight.
 5. The method of claim 1, in which the therapeutically effective amount is administered at least once daily and no more than once hourly.
 6. The method of claim 1, further comprising administering at least one free radical scavenger or inhibitor.
 7. The method of claim 1, in which the therapeutically effective amount is sufficient to provide at least 5 nanograms per milliliter and no greater than 10 milligrams per milliliter of the α₁-antitrypsin, an oxidation-resistant α₁-antitrypsin Met358 variant, or a free radical-resistant α₁-antitrypsin M358 variant inhibitor in the biological fluid of the subject.
 8. The method of claim 7, in which the biological fluid is blood.
 9. The method of claim 7, in which the therapeutically effective amount is sufficient to provide at least 0.5 μM and no greater than 100 μM in the biological fluid of the subject.
 10. The method of claim 1, in which the administering is parenterally, orally, vaginally, rectally, nasally, buccally, intravenously, intramuscularly, subcutaneously, intrathecally, epidurally, transdermally, intracerebroventricularly, by osmotic pump, by inhalation, or combinations thereof.
 11. A method for treating muscular dystrophy, multiple sclerosis, arteriosclerosis, neurodegenerative disease, myocardial infarction, or stroke in a subject in need of such a treatment, said method comprising administering to the subject a therapeutically effective amount of α₁-antitrypsin, an oxidation-resistant α₁-antitrypsin Met358 variant or a free radical-resistant α₁-antitrypsin M358 variant.
 12. The method of claim 11, wherein the neurodegenerative disease is Alzheimer's disease or Down's Syndrome.
 13. The method of claim 11, in which the subject is a human.
 14. The method of claim 11, wherein the effective amount of α₁-antitrypsin, an oxidation-resistant α₁-antitrypsin Met358 variant, or a free radical-resistant α₁-antitrypsin M358 variant is at least 0.001 g/kg body weight and no greater than 1 g/kg body weight.
 15. The method of claim 11, in which the therapeutically effective amount is administered at least once daily and no more than once hourly.
 16. The method of claim 11, further comprising administering at least one free radical scavenger or inhibitor.
 17. The method of claim 11, in which the therapeutically effective amount is sufficient to provide at least 5 nanograms per milliliter and no greater than 10 milligrams per milliliter of the α₁-antitrypsin, an oxidation-resistant α₁-antitrypsin Met358 variant, or a free radical-resistant α₁-antitrypsin M358 variant inhibitor in the biological fluid of the subject.
 18. The method of claim 17, in which the biological fluid is blood.
 19. The method of claim 17, in which the therapeutically effective amount is sufficient to provide at least 0.5 μM and no greater than 100 μM in the biological fluid of the subject.
 20. The method of claim 11, in which the administering is parenterally, orally, vaginally, rectally, nasally, buccally, intravenously, intramuscularly, subcutaneously, intrathecally, epidurally, transdermally, intracerebroventricularly, by osmotic pump, by inhalation, or combinations thereof. 